Funnel and thread guard



- May 7, 1957 o. MAISCH FUNNEL AND THREAD GUARD Filed May 22, 1951 United States Patent Oflice 2,791,148 Patented May 7, 1957 FUNNEL AND THREAD GUARD Oliver Maisch, Chicago, Ill.

Application May 22, 1951, Serial No. 227,685

3 Claims. (Cl. 86-31) In the manufacture of high explosive shells, whether of bazooka or artillery type, the charge of high explosive, TNT, is introduced in liquid form through a funnel; the latter being inserted loosely in the screw-threaded opening in the top of the shell. Because the explosive shrinks greatly in volume in solidifying from the liquid state, this conventional filling process presents problems which make it much more costly than a simple pouring operation. Obviously, the liquid must rise to a higher level than the predetermined level to which the solid explosive can be allowed to reach, to compensate for the subsequent shrinkage. As a result, some of the liquid rises around the outside of the tubular part or stem of the funnel and spirals up into the screw threads, where it solidifies. The accumulation of explosive must afterwards be removed from the screw threads to an exact distance from the top of the shell and, moreover, considerable trimming of the top of the solidified charge is usually required.

An object of the present invention is to provide simple and novel means to prevent the explosive from rising into the screw threads, no matter how high the liquid level within the funnel may be.

In the preferred form of my invention I employ a sleeve of rubber or rubber-like material that may be slipped freely into and out of the screwthreaded inlet in the top of the shell, together with a funnel which, when inserted in the sleeve, expands the same and causes it to mesh effectively with the threads and form a tight seal between the funnel and the surrounding shell.

Since the lower end of the seal and the lower end of the funnel serve as a dam against rising liquid I utilize them to establish the predetermined top surface of the solid charge over an annular area of considerable radial width; thereby causing the funnel device to serve as a gauge as well as a mere filling and thread sealing means. In that sense my invention may be regarded as having for an object to create a simple and novel funnel device which shall effectively seal itself in an opening or bore and constitute a gage to determine the level to which liquid may rise, as well as being a die to determine the contour of a wide marginal area of the top of body formed by the solidification of such liquid.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out in the claims; but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawing, wherein;

Figure 1 is a longitudinal sectional view through the funnel element of my new device; Fig. 2 is a view, partly in elevation and partly in section, showing a small, empty shell having my novel sealing element loosely set into the same preparatory to the insertion of the funnel; Fig. 3 is a view, partly in elevation and partly in section showing a fragment of the shell, the funnel and the sealing element assembled ready for pouring; Fig. 4 is an axial section through the sealing element, by itself; Fig.

5 is a top plan view of the sealing element; and Fig. 6 is an axial section showing fragments of a shell and a modified funnel assembled as in Fig. 3.

In the drawing, 1 is a small ammunition shell open and internally screw-threaded at its upper end; 2 indicating the screw threads. In this particular construction the screw-threaded bore is assumed to be longer than the male member that is to cooperate therewith and, therefore, it is of no consequence whether or not some of the inner or lower threads are left exposed while the shell is being filled with explosive material.

3 is a funnel which may take any desired form, preferably having a short cylindrical tube or spout 4 surrounded at the upper end by a flat, annular shoulder 5; the diameter of the tube or spout being substantially less than that of the screw-threaded bore in the shell.

6 is a cylindrical sleeve of rubber-like material, such as natural or synthetic rubber. The external diameter of the sleeve is such that the sleeve may be moved freely into and out of the screw-threaded bore in the shell. The internal diameter of the sleeve is preferably about the same as the external diameter of the spout. On one end of the sleeve, namely the upper end, is an external annular flange 7 having fiat upper and lower surfaces. This flange limits the entry of the sleeve into the opening in the shell. The length of the sleeve, below the flange, is at least equal to that of the section of the screw thread to be protected. The sleeve wall is thickened on the inner side at and inwardly from the lower end; preferably by gradually decreasing the internal diameter to create a constricted bore section surrounded by a surface 8 in the form of an inverted frustum of a cone.

When a shell is to be charged, the sealing sleeve is slipped into the open upper end of the shell until its flange rests on the end face of the shell, as shown in Fig. 2. The spout of the funnel is then inserted in the sleeve, downward movement of the funnel being unimpeded until the lower end of the spout reaches the sloping surface 8 of the sleeve. Thereafter, by forcing the funnel down, the lower portion of the sleeve is deformed, the bore becoming cylindrical throughout its length and the thickening of the wall becoming external. There is enough excess rubber in the thickened area to fill the valley in the thread that spirals around the sleeve for an angular length of at least one complete turn, and preferably, several turns as shown in Fig. 3.

With the parts in the positions which they occupy in Fig. 3, the flange 7 forms a cushion and seal between the body of the funnel and the shell, while the lower half of the sleeve provides an effective filler for the valley component of several complete turns of the threads in the shell. Therefore liquid may be poured into the shell without the slightest danger that any of the same wiii later be found on any thread that must be kept clean for cooperation with a mate thread. After the pouring is completed the funnel is allowed to remain in the shell until the explosive solidifies.

It is obvious that the lower edge faces of the sleeve and the funnel serve as a gauge to set the level which the top of the charge in the shell may reach in the annular area surrounding the bore in the lower end of the spout and, also, that these elements act as dies to give shape to this part of the face at the top of the charge.

When the funnel is removed such core of solid explosive as extends up into the funnel is broken off, as heretofore, leaving only a small central area that requires trimming.

In Fig. 6 there is shown a funnel the tubular element or spout of which has been fashioned to define the fuse Well which heretofore has been cut into the solid body of explosive. The shoulder 10 on the spout corresponds to the lower edge face of the other funnel, the Wall of the 3 spout being gradually thickened on the inner side and extended down, as at 11, to provide a part of the same diameter as the desired fuse well and having a length equal to the depth of the well, Upon removing the funnel, after a charge has been poured and become solidified, no further work need be done on the well except, perhaps, to finish or trim the bottom where the core was broken off.

I claim:

1. A funnel means for sealing threads in an internally screwthreaded opening, comprising a flexible, rubber-like sleeve of a size to fit easily in said opening, the sleeve having at one end an external flange to rest on the member in which said opening is located and having its wall progressively thickened on the inner side toward the other end, and a funnel having a cylindrical, externally smooth spout that is a sliding fit in the portion of the sleeve bore surrounded by the unthickened part of the sleeve wall and that is sufliciently long to extend into that part of the bore surrounded by the thickened sleeve wall.

2. A funnel means for sealing threads in an internally screwthreaded opening, comprising a flexible, rubber-like sleeve of a size to fit easily in said opening, the sleeve having at one end an external annular flange to rest on the member in which said opening is located and having its wall progressively thickened on the inner side toward the other end, and a funnel having a cylindrical, externally smooth spout that is a sliding fit in the portion of the sleeve bore surrounded by the unthickened part of the sleeve wall and that is sufliciently long to extend into that part of the bore surrounded by the thickened sleeve wall, and the funnel having an annular shoulder to rest on the flanged end of the sleeve when the spout is pushed into the latter.

3. A device for filling an ammunition shell with an explosive in a molten state, which comprises a rubber-like sleeve and a funnel, the funnel having a cylindrical, externally smooth spout longer than and being a sliding fit in the sleeve, the funnel also having a shoulder to engage one end face of the sleeve when the spout is inserted in the sleeve and projects a predetermined distance beyond the opposite end, and the bore in the sleeve toward the latter end being thickened inwardly so as to have a diameter that becomes progressively smaller as the latter end is approached; whereby expanding pressure on the sleeve is exerted only at the thickened end, in use, and the protruding portion of the spout creates a fuse well in the explosive when the same hardens.

References Cited in the file of this patent UNITED STATES PATENTS 1,477,040 Davidson Dec. 11, 1923 1,508,395 Isham Sept. 16, 1924 1,899,095 Knight Feb. 28, 1933 2,311,694 Rogers Feb. 23, 1943 2,350,181 Morgan May 30, 1944 2,352,207 Knight June 27, 1944 FOREIGN PATENTS 113,366 Germany July 15, 1899 

